Electrical protective device.



W. 0. LUM.

ELECTRICAL PR-OTECTIVE DEVICE.

APPLICATION FILED OCT. 23. 1913.

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ATTORNEY Patented Apr. 1,

W. 0. LUML V ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED OCT. 23. 1913.

Patented Apr. 1

'z/m/mlxm' WWW 2 SHEETS-SHEET 2 l VENTOR ATTORNEY WALTER O. LUM, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A. CORPORATION OF PENNSYLVANIA.

ELECTRICAL PROTECTIVE nnv icn.

Specification of Letters Patent.

Application filed October 23, 1913. Serial No. 796,866.

To all whom it may concern:

Be it known that I, WALTER O. LUM, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Protective Devices, of which the following is a specification.

lvfy invention relates to electrical protective devices, and particularly to locking devices for circuit interrupters. v

The object of my invention is to provide a device for preventing the operation of a circuit interrupter by anyone other than an authorized party.

Since switches are sometimes located in places which are accessible to unauthorized parties, and considerable harm may be done when such switches are operated at improper times, I have provided a locking device to prevent the operation of a switch blade except by the use of a key. I provide also auxiliary means for looking a switch blade in its extreme position.

In the accompanying drawings, Figure 1 is a plan view of a knife blade switch and a locking device embodying my invention. Fig. 2 is an elevational view of the looking device shown in Fig. 1. Fig. 3 is a sectional view taken along the line IIIIII of Fig. 2. Fig. 4: is an elevational view of a key device which is embodied in my invention. Fig. 5 is a sectional View taken along the line V-V of Fig. 4:, and Fig. 6 is a detail View of the bolt and spring member used in my invention.

Referring to the drawings, my invention is adapted to protect an ordinary knife blade switch 1 having a knife blade member 2, a contact terminal 3 and a terminal member 4:, upon which the knife blade member 2 is pivotally mounted. My invention comprises, in general, a frame work 5, a bolt 6, a helical spring 7 attached to the bolt 6 by an angular piece 8, and an operating key 9. The frame work 5 has a slot 10 therein for receiving the blade 2 of the knife blade switch 1, an irregular shaped opening to receive the key 9 and a plurality of circular openings 11 for locking the bolt 6 by an auxiliary means (not shown) in its extreme position. The bolt 6 has a cylindrical projection 12 at one side, and a plurality of openings 13 for coiiperating with the openings 11. The key 9 is provided with a fluted portion 14, for engaging a fluted opening in .the notch 15 is reached.

The bolt 6 is. guided by slots in the frame work5, and, when in its normal position,

its end iss'eated in a recess 16, the walls of which constitute a catch. The frame work 5, for simplicity of construction, is made in two parts 17 and 18 that are riveted together by rivets 19, and these parts are severally provided with laterally projecting feet 20 and 21. The key 9, as hereinbefore stated, is fluted in order that it may be inserted with ease in a similarly fluted opening in the frame work 5 and be prevented from moving in a transverse direction.

When the key 9 is inserted in the fluted slot provided therefor, it engages the projection 12 and moves it and the bolt 6 rearwardly against the action of the spring 7 until the notch 15 is reached by the projection. This action withdraws the bolt from the recess 16 of the frame work 5 and thus permits unobstructed movement of the knife blade 2. The bolt 6 will remain in its retracted position until the key 9 is removed from its slot.

When the key 9 is withdrawn from the slot, the spring 7, which has been co1npressed, will move the bolt 6 outwardly across the slot 10 into its recess 16 to prevent operation of the knife blade 2. The openings 11 and 13 are so located that a plurality of pad locks (not shown) may be inserted therein to lock the bolt 6.

Various modifications may be made in the mechanical structure of my invention and various means of applying it to the protection of circuit interrupters may be made without departing from the scope of the same as set forth in the appended claims.

I claim as my invention:

Patented Apr. 1, 1919.

1. A locking device comprising a non-pivoted slidable bolt having a projection extending laterally therefrom, resilient means for moving the bolt in one direction, and a non-rotatable key adapted to cooperate with the projection to move the bolt in the opposite direction, said key having a notch therein for engaging the projection to retain the same in a predetermined position.

2. A locking device comprising a housing,

a bolt disposed in the housing, a spring for moving the bolt in one direction, and a key having two bearing portionsand a connect-v ing handle, one bearing portion of the'key being adapted to be inserted in the housing to actuate the bolt and the other bearing portion being adapted to extend in a channel on the. outer surface of the housing 3. A locking device comprising a bolt.

having a projection thereon, a spring for actuating said bolt in one direction, and a non-rotatable key adapted to. engage the bearing portions and a connecting handle, one bearing portion of the said key adapted to be inserted in the housing to engagethe' projection: on the bolt and the other bearing portion adapted to extend in a channel in the housing.

5; A locking device comprising a housing, a vbolt disposed in the housing, means for actuatingthebolt in one direction, and a key for actuating the bolt in the opposite direction, said key having a notch therein for en gaging a portion of the bolt to retain the samein one position.

In testimony whereof I havehereunto subscribed my name this l7th day of October,

WALTER O. LUM.

Witnesses:

M. J. Bo'rHWELL, B. B, HINES.

Gopiesoi this patent may be obtained for five oents each, byaddres sing the Commissioner of Patents,

' Washington, D. 0. 

